{"cve":"CVE-2026-59884","nvd":{"published":"2026-07-14T17:17:14.750","modified":"2026-07-21T14:37:52.160","status":"Analyzed","description":"pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the BER decoder shared by the CER and DER codecs parses long-form tags by accumulating continuation octets without an upper bound on the tag ID size, allowing a crafted input to force construction of an arbitrarily large integer with CPU cost growing quadratically and to trigger unhandled ValueError exceptions in Python 3.11+ error formatting paths. Any application decoding untrusted BER, CER, or DER input is affected. This issue is fixed in version 0.6.4.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-400"],"references":["https://github.com/pyasn1/pyasn1/commit/628e36ecbb5277a3f01572ce418ef54271b165a5","https://github.com/pyasn1/pyasn1/releases/tag/v0.6.4","https://github.com/pyasn1/pyasn1/security/advisories/GHSA-m4p7-r5rc-7g4j"],"products":["pyasn1:pyasn1"],"source":"nvd","synced_at":"2026-10-19T22:44:02.134301115+00:00"},"epss":{"cve":"CVE-2026-59884","score":0.00616,"percentile":0.4954,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-m4p7-r5rc-7g4j","url":"https://osv.dev/vulnerability/GHSA-m4p7-r5rc-7g4j","summary":"pyasn1 BER/CER/DER decoder denial of service via unbounded long-form tag IDs","modified":"2026-09-10T03:50:52.562707948Z","packages":[{"ecosystem":"PyPI","name":"pyasn1","purl":"pkg:pypi/pyasn1","ranges":["<0.6.4"],"fixed":["0.6.4"]}]},{"id":"PYSEC-2026-3455","url":"https://osv.dev/vulnerability/PYSEC-2026-3455","summary":"","modified":"2026-07-22T11:00:08.839373736Z","packages":[{"ecosystem":"PyPI","name":"pyasn1","purl":"pkg:pypi/pyasn1","ranges":["<0.6.4"],"fixed":["0.6.4"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}